Lingual Dentition of Gmotis. 253 



dentate, laterals scarcely differing from the centrals, mar- 

 ginals lengthened, awl-shaped, arcuate, at base ? bifurcate. 

 The presence of a jaw was not verified by Shuttleworth. 

 The character of the dentition was considered such as to 

 denote carnivorous habits of the animal. 



This is all the information as to the lingual dentition of 

 Gceotis hitherto published. Morch, indeed, places the genus 

 (Jour, de Conch. 1865, 384) in his section Odontogiiatha, 

 which comprises the Terrestrial Pulmonata furnished with a 

 ribbed jaw, not from any original investigations, but simply 

 from its assumed identity with Parmacella , a genus believed 

 to have a ribbed jaw, judging from the obscure figure given 

 by Ferussac of the mouth of Parmacella palliolum (Hist. t. 

 8 A, fig. 8). Shuttleworth's descr'ption rather indicates the 

 form of dentition figured by us (Land and Fresh Water 

 Shells, I), of many species of Vitrina, Ilyallna and Zonites. 

 The bifurcated base of the marginal teeth may even be sup- 

 posed to be such as we have figured {I. c. 17) in the centrals 

 of Glandina truncata. 



We have long had in our possession the jaw and lingual 

 membrane of a specimen of Gmotis from Porto Rico. The 

 animal was received many years ago by one of us (Bhmd) 

 from the late Mr. Robert Swift, the alcohol in which it was 

 originally preserved evaporated, and the jaw and lingual 

 membrane were, not very long since obtained, by macera- 

 tion, in a somewhat imperfect condition. Comparing the 

 latter with Shuttleworth's description, we find that at first 

 we had misunderstood his words, which, indeed, are quite 

 liable to mislead, especially in the infelicitous comparison 

 with Vitrina and Zonites. We give, therefore, a more de- 

 tailed description and figure, in order to prevent further 

 errors. 



Jaw (plate xi, fig. 1) long, low, slightly arcuate, ends attenuated, ex- 

 tremely thin and delicate, transparent : in one single piece, but divided b}' 

 over forty* delicate ribs into as many plate-like compartments of the type 



* Fragments only of the jaw were saved ; the largest one we have figured, and from 

 it estimate the whole number of ribs. 



